Cement clinker substitution occurs when clinker, the primary material used in cement manufacturing, is substituted with other cementitious materials, such as coal fly ash or blast furnace slag. Because these materials are byproducts of other industrial and energy processes and can displace the need to create clinker, the use of these substitutes can significantly lower process emissions in cement manufacturing.

Many policies can be used to support cement clinker substitution. One common approach is to standardize cement types, as has been done in Europe. Under this approach, the government sets criteria standards for cement types, to which cement manufacturers must adhere. Establishing different classes for cement helps ensure cement purchasers of the quality and performance of the cement being purchased. These standards can also create markets for cements with lower clinker ratios.

Other policies promoting clinker substitution focus on rewarding cement manufacturers for using recycled materials or creating incentives for co-locating cement kilns with other industrial facilities that produce clinker substitutes as by-products.

For a more detailed discussion, see the applicable chapter of Designing Climate Solutions, our book on smart energy and climate policy design.